Booster apparatus for mining machines



Dec. 21, 1954 F. B. MILLER BOOSTER APPARATUS FOR MINING MACHINES 4sheets-sheet 1 Filed Sept. 2, 1950 INVENTOF Dec. 21, 1954 F. B. MILLERBOOSTER APPARATUS FOR MINING MACHINES Filed Sept. 2, 1-950 4Sheets-Sheet 2 MN KN INVENTOE All Dec. 21, 1954 F. a. MILLER BOOSTERAPPARATUS FOR MINING MACHINES 4 Sheets-Sheet 3 Filed Sept. 2, 1950 Dec.21, 1954 F. B. MILLER BOOSTER APPARATUS FOR MINING MACHINES 4Sheets-Sheet 4 Filed Sept. 2, 1950 INVENTOI? MWWWWWM United StatesPatent BOOSTER APPARATUS FOR MINING MACHINES Frederick B. Miller,Chicago, Ill.

Application September 2, 1950, Serial No. 182,955

7 Claims. (Cl. 262-12) The invention relates to mining machines adaptedto undercut coal at the face of the mine, break down the coal that hasbeen undercut and load the coal cuttings from the undercut and also thecoal broken down above the undercut or kerf.

To accomplish the operation of breaking down the coal above the kerf bymeans of an hydraulic reciprocating dislodging member, it is known thatgreater pressures are required the deeper the dislodging member isforced into the coal face, so that to dislodge the coal toward the endof the stroke requires more pressure than at the beginning of thestroke. Of course, the installation could be designed for the maximumpressures required but the cost would be excessive for a competitivemachine. Therefore, the invention contemplates an installation whichwill supply the average pressures required for breaking down the coal atthe mine face and which will augment the same by booster mechanism thatwill derive energy from the return stroke of the dislodging member anddeliver it at a predetermined instant in the forward stroke of saidmember.

Accordingly, a main object of the invention is to provide a boostercylinder adapted to become operative near the end of the working strokeof the dislodging member to provide that additional pressure requiredfor driving said member into the coal face for its full working stroke.

Another object is to provide an accumulator in combination with thebooster cylinder and which is charged by said booster cylinder since theaccumulator receives a discllgarge of fluid from the booster cylinder onits. return stro e.

A further object is to provide means for interconnecting the boostercylinder piston with a main cylinder piston whereby the pressureactuated main cylinder piston on its return stroke imparts movement tothe booster cylinder piston for returning the same.

Another object of the invention is to provide booster apparatus for amining machine which has a reciprocatinc dislodging member for breakingdown the coal at the mine face, wherein the booster ap aratus includesan accumulator that is charged with fluid at hi h pressure as a resultof the return stroke of the dislod ing member, and wherein saidaccumulator is automaticallv dischar ed to the booster cvlinder towardthe end of the working stroke. thus driving the dislodging member intothe coal face f r its full stroke.

With these and various other obiects in View, the inven tion may consistof certain novel features of construction and operation, as will be morefully described and particularly pointed out in the specification,drawings and claims appended hereto.

In the drawings which illustrate an embodiment of the device and whereinlike reference characters are used to desi nate like parts- Figure 1 isa plan view of a mining machine incorporating the improvements of thepresent invention;

Figure 2 is a side elevation of the machine of Figure'l taken on lineIIII of said figure and showing the booster cylinder and in part sectionthe hydraulic jack in conjunction with the anchor bars;

Figure 3 is an end elevation of the machine taken on line IIIIII ofFigure 1 and showing the rear end of the main and booster cylinders;

Figure 4 is a transverse section of the conveyor, taken on line IVIV ofFigure 1 and showing the conveyor in relation to the cu ter chains;

ICC

Figure 5 is a fragmentary detail view, part elevation and part section,taken on line VV of Figure 1 and showing details of the hydraulic jackin conjunction with the anchor bars in retracted position;

Figure 6 is a diagrammatic view of the fluid circuit showing the tank,pump, main cylinder, booster cylinder, accumulator, and the valves forcontrolling flow;

Figure 7 is a fragmentary view of the quadrant gears, taken on lineVIIVII of Figure l; and

Figure 8 is a plan view of Figure 7.

Referring to the details of the machine illustrated in the drawings,particularly Figure 4, the main frame 10 is pivotally mounted ontransverse cross member 11, the said cross member being formed integralwith a pair of longitudinal endless-tread supporting side frames 12-12and which are provided with a front idler sprocket 13, a drive sprocket14, and pivotally connected shoes 16 comprising the endless caterpillartreads 17, 17 of well known construction. The drive sprocket 14 is fixedto a drive shaft 15 which is driven by any suitable source of power. Asecond cross member 18 is formed integral with the side frames 12, 12. Apair of cylinders 19, 19 are piv otally mounted on the second crossmember 18. A piston 20, reciprocably mounted in each of the cylinders19, 19 is fixed to a piston rod 21, the said rod being in turn pivotallyconnected to the main frame 10. Hydraulic pressure is supplied to thecylinders 19 for tilting the main frame, it being understood that thehydraulic pressure may be derived from a fluid pump under the manualcontrol of suitable valves.

A pair of cutter chain guides 22, 22, Figure l, is fixed to the forwardend of the main frame 10 and in each of the guides there is operativelymounted a cutter chain 23 of usual construction, driven by sprocket 24fixed to a drive shaft 25, said shaft being iournalled in housing 26, asbest shown in Figure 2. Shoes 27. 27 are provided at the forward end ofeach cutter chain guide, being located on the top and bottom thereof,and the shoes are adapted to bear respectively against the top andbottom surfaces of the kerf, which is cut by the cutter chains uponoperation thereof. A single endless conveyor belt 28, Figure 4, isdriven by a pulley 29, said pulley being fixed to drive shaft 30,journalled in the rear of main frame 10. At its forward end the conveyorbelt is trained over a pulley 31 journalled on a shaft 32, which is alsofixed to the main frame at the forward end thereof adjacent to and inthe path of the cutter chains 23, 23. Said chains are adapted to rakeand crowd the cuttings onto the conveyor belt whereby said cuttings aredelivered to the rear of the machine.

A pair of hydraulic jacks is associated with the cutter chain guides,each hydraulic jack including a cylinder 33, Figure 2, which extendsthrough and is fixed to one of the cutter chain guides 22. The piston34, reciprocably mounted in the cylinder 33, is provided with a pistonrod 35. The head 36 of each piston rod 35 is suitably guided in thelower portion of its cylinder 33 and the rear end of an anchor bar 38has interfitting and articulated relation with each piston rod head 36.The anchor bars 38 are each pivotally mounted in a slot 37 by means of apin 39 and upon actuation of the piston 34 in a direction upwardly, theforward portion of the anchor bar is caused to en age and press againstthe floor of the mine. Each cylinder 33 is provided with openings 40, 40to receive pi es through which pressure fluid may be supplied to thecylinder as by means of a fluid pump under manual control of suitablevalves.

The combined action of the anchor bars in pressing downwardly againstthe mine floor and that of the shoes on the forward end of the cutterguides in pressing upwardlv against the to surface of the kerf locks thefmachine in a coal minin osi ion and the reactive forces caused by thethrusts of the dislod ing member are effectively resisted. For a moreparticular description of the anchoring means reference is made to mycopending application Serial No. 171,135, filed June 29, 1950, andentitled Mining Machine.

Mounted on the main frame 10 is a mechanism for breaking down the coalsimilar to that shown and described in my prior Patent No. 2,368,863,dated Februthe rear of said cylinder.

ary 6, 1945. The mechanism consists of a pair of spaced uprightsupporting brackets 41 and 42, Fig. 3,'which journal the horizontalshafts 43 and 44 extending in spaced relation transverselyof themachine. Carriage guide members 45 and 46 are fixedly connected by thetrunnion member 46a, and which provides means for journalling the guidemembers 45 and 46 on shaft 43. Quadrant gear 47 is keyed to shaft 44,said gear 47 having meshing relation with quadrant gear 48. Since gear48 is integral with guide member 45, rotation of shaft 44 by anysuitable source of power, not shown, will produce a swinging movement ofthe carriage guide members 45 and 46 with respect to shaft 43 as atransverse axis. The guide members are each provided with a bearingportion identified by numerals 49 and 50, respectively, on which rambars .51 and 52 are slidably mounted. The ram bars form the sides of areciprocable carriage, said bars being connected so as to complete thecarriage by means of a carriage base plate 53. It will be understoodthat ram bars 51 and 52 are adapted to reciprocate in their respectivebearing portion 49 or 50, which reciprocation is effected by the rackportions 54. which have meshing relation with rack pinions 55, keyed tothe shaft '43. Said shaft 43 provides the drive shaft for oscillatingthe rack pinions 55, which may be driven in reversible directions by asource of power, not shown. A wedge plate 56, comprising'the coaldislodging member, isjsecured to the carriage base plate 53, and as thecarriage is reciprocated to produce successivethrusts of the wedge platethe coal at the mine face is dislodged. Integral with the carriage baseplate -53 are side cutters-59, 59 adapted to provide clearance forvertical'swinging movement of the wedge plate 56. g a

In operation of the mining machine as disclosed, the

main frame is fedforwardly to engage the cutter chains 23, 23 withthe'coal face, and thereby cut a kerf in the coal face adjacent thefloor of the mine. Cuttings from the kerf are raked backwardly andcrowded onto the conveyor belt 28by the cutter chains. When the cutting'of thekerf to a predetermined depth has been completed fluid isdirected into the cylinders 33, 33 to impart movement to the pistons 34thereof, and cause the forward end of the anchor bars 38, 38 to bepressed against the mine floor, thus locking the mining-machine inposition for operation. To drive the wedge plate 56 into the coal to bemined requires hydraulic mechanism for reciprocating the carriagewhereby thrusts ofthe wedge plate take place in succession. For eachthrust the carriage is moved upwardlya predetermined extent from alowermost forwardly inclined position. The invention provides anhydraulic booster cylinder in combination-with the hydraulicreciprocating mechanism for the wedge plate, said booster providing theadditional force required for driving the wedge plate into the materialto be mined for the full stroke of the carriage. described.

As best shown in Figure 6, the main cylinder 60 and the booster cylinder61 are pivotally connected by means of pins 61a to the trunnion 460.,which trunnion serves as a transverse connection for the guide membersand 46. The main cylinder and the booster cylinder 61 are each providedwith a piston 62 and 63, respectively, the said pistons having pistonrods 64 and .65 and which are pivotally connected to the carriage baseplate 53 by means of pins 65a. The main reservoir tank 66 is mounted onthe main frame as is also the fluid pump 67, the selector valve 68, theaccumulator 69, the pressure actuated valve 70, the relief valve 71, andthe, check valves 72 and 73. Since the accumulator and valves are 'ofknown construction, it s not deemed necessary to describe'them inspecific detail. Fluid line 74 connects the pump 67 to the tank 66.Fluid line 75 connects the pump 67 with the selector valve 68, whereasthe selector valve This mechanism will now be v is connected to theforward end and to the rear end of the main cylinder 60 by lines 76 and77, respectively. The said selector valve is also connected to thereservoir tank 66 by the fluid line 78. The pressure actuated valve 70is connected to the accumulator '69 by fluid line'79and to the boostercylinder 61 by the fluid line 80. i The fluid line 81 connects thepressure actuated valve 70 'with line 77 and thus said 'valve'communicates and joins with the fluid connections to the main cylinder.Thefluid line 83 is provided with the check valve 72, the structureconnecting the accumulator 69. with the booster cylinder 61 at FIuidline 84..is provided with the check valve 73, and through fluid linesand 8 2 the structure connects the rear of booster cylinder 61 with thereservoir tank 66. Oneach forward stroke of the booster cylinder fluidis withdrawn from the reservoir tank, the check valve 73 permitting suchaction. Connected to the forward end of the booster cylinder is abreather valve 85 of any known construction.

The carriage and thus the wedge plate 56 are reciprocated for breakingdown the material to be mined by actuating the selector valve 68 so asto selectively direct pressure fluid from the fluid pump 67 torespective ends of the main cylinder 60. For example, to drive thecarriage and the wedge plate in a forward direction, pressure fluid isadmitted to fluid line 77 connecting with cylinder 60 at the rearthereof, and fluid line 76 is connected to reservoir tank 66 so that theforward end of cylinder 60 is simultaneously exhausted. As piston 62 ofcylinder 60 is driven in a forward direction the piston 63 of thebooster cylinder 61 will likewise move in the same direction. Duringforward travel of piston 63 the booster cylinder 61 is supplied withfluid from tank 66 by fluid line 82, check valve 73 and fluid line 30.To return the carriage and thus the wedge plate 56 the selector valve 68is manipulated so as to supply pressure fluid to line 76 connecting withthe forward end of cylinder 60. Simultaneously therewith line 77 will beconnected to reservoir tank 66 so as to exhaust the rear of thecylinder. Piston 63 of the booster cylinder 61 will move in a returndirection in unison with piston 62 of the main cylinder and during saidreturn stroke fluid line 83 and check valve 72 are operative and fluidfrom the booster cylinder 61 is directed into the accumulator 69, thesaid fluid being forced into the accumulator against the tension of itscoil spring and accordingly the accumulator is charged with pressurefluid on each return stroke of piston 63 of said booster cylinder 61.

In accordance with the invention the accumulator 69 is released to thebooster cylinder at a predetermined point in the forward stroke of thewedge plate in order to supply additional pressure fluid for driving thewedge plate to complete its full working stroke in said forwarddirection. The pressure actuated valve 70 functions to control therelease of the accumulator 69, the valve being interposed between thefluid lines 79 and 80 and having connection by means of fluid line 81 tothe selector valve 68 and thus also communicating with the fluid line 77which supplies pressure fluid to the rear of the main cylinder. Valve 70is so constructed and arranged as to be responsive to a predeterminedmaximum pressure such as may be developed in fluid line 77. During thereturn stroke of said carriage and wedge plate 56, the fluid pressuresdeveloping in line 76 will be a minimum since the forces resistingtravel of the carriage and wedge plate in a return direction are aminimum. However, as regards the forward working stroke of the wedgeplate, higher operating pressures will develop in the fluid line 77since the wedge plate encounters considerable resistance in being forcedinto the coal face to cause a breaking down of the coal being mined.This resistance to forward movement of the wedge plate progressivelyincreases as the wedge plate is forced deeper and deeper into the coalface. Accordingly, toward the end of .the forward working stroke. theoperating fluid pressures in the line 77 will reach a maximum and saidworking pressures may exceed the pressure of the fluid normallydelivered by the pump, Since line 81 has connection with fluid line 77the excessive fluid pressures developed therein are transmitted to thepressure actuated valve 70. Therefore as the wedge plate 56 reaches theend of its,working stroke in a forward direction, at which time itencounters the maximum resistance to its continued forward movement, thepressure actuated valve 70 is automatically operated to release theaccumulator 69 to the booster cylinder 61. This supply of additionalpressure fluid from the accumulator to the booster cylinder provides theadditional force requircd to drive the wedge plate into'the coal to bemined for the full forward stroke of the wedge plate.

Upon 'completionof the breaking down of the successive portions of coalto a predetermined height above the kerf, the fluid in the cylinders33-33 is released so that with the pressure on the anchor bars 3838being removed the said bars can be reset in a horizontal retractedposition. The mining machine is now free to be moved forwardly .tocutanother kerf in the .coal face by operation of the cutter chains 23. Asthe mining machine is moved forwardly during a kerf 'cutting operationthe broken down coal resting on the cutter chain guides 22-22 is movedup the inclined portion 57 onto the endless belt 28. The flared ribs58--5 8, formlng part of the main frame 10, are adapted to guide theflow of coal into the path of said endless conveyor belt.

The invention is not to be limited to or by details of construction ofthe particular embodiment thereof illustrated by the drawings as variousforms of the device w ll of course be apparent to those skilled in theart without departing from the spirit of the invention or the scope ofthe claims.

I claim:

1. In a mining machine having a main frame, guides mounted for verticalswinging movement relative to sa d main frame, a carriage reciprocablymounted in said guides and providing a dislodging member adapted tobreak down the material to be mined, a main cylinder and a boostercylinder having pistons respectively connected to the carriage forreciprocating the same, a fluid pump and a selector valve connected tothe main cylinder for selectively supplying pressure fluid to respectiveends of said cylinder for reciprocating its piston, a fluid reservoirand a check valve connected to the rear of the booster cylinder andoperative to supply fluid to the cylinder as a result of forward travelof its piston, an accumulator and a check valve also connected to therear of the booster cylinder whereby the accumulator is charged withpressure fluid from the booster cylinder upon the return stroke of itspiston, other means for connecting the accumulator with the rear of thebooster cylinder, said other means including a pressure actuated valvehaving communication with the connections to the main cylinder, and saidpressure actuated valve operating automatically during the forwardstroke of the carriage when a predetermined pressure exists in theconnections to the main cylinder to connect the accumulator with thebooster cylinder, whereby the said booster cylinder provides theadditional force required to drive the dislodging member into thematerial to be mined for the full stroke of said member.

2. In a mining machine having a main frame, guides mounted for verticalswinging movement relative to said main frame, a carriage mounted forreciprocating movement in said guides and providing a dislodging memberadapted to break down the material to be mined, a main cylinder having apiston connected to the carriage for reciprocating the same, a boostercylinder also having a piston connected to the carriage, selector valvemeans and connections leading to respective ends of the main cylinderfor selectively supplying pressure fluid to said cylinder forreciprocating its piston, means connected to the rear of the boostercylinder and operative to supply fluid to the cylinder as a result offorward travel of its piston, an accumulator also connected to the rearof the booster cylinder, said connections including a check valvewhereby the accumulator is charged with pressure fluid from the boostercylinder upon the return stroke of its piston, other means including apressure actuated valve for connecting the accumulator with the rear ofthe booster cylinder, said valve having communication with theconnections to the main cylinder, and said pressure actuated valveoperating automatically during the forward stroke of the carriage as aresult of a predetermined pressure increase developing in theconnections to the main cylinder to connect the accumulator with thebooster cylinder, whereby the said booster cylinder provides theadditional force required to drive the dislodging member into thematerial to be mined for the full stroke of said member.

3. In a mining machine having a main frame, a dis lodging member mountedby the frame for reciprocating movement relative thereto, motor meansfor reciprocating said dislodging member to break down the material tobe mined, said motor means including first and second cylinders, apiston mounted for reciprocation in each cylinder and operativelyconnected to said dislodging member, a fluid pump, means for selectivelysupplying pressure fluid from said fluid pump to re spective ends of thefirst cylinder for reciprocating the piston of said cylinder and thusthe dislodging member, an accumulator, other means for directing fluidfrom the second cylinder to the accumulator on each return stroke of thepiston of said cylinder, whereby the accumulator is charged withpressure fluid from said second cylinder, additional connections betweenthe accumulator and said second cylinder, and a pressure actuated valve111 said connections responsive to the operating fluid pressures of saidpump, said valve operating automatically during the forward stroke ofthe dislodging member when the operatingfluid pressures of the pumpexceed a maximum value to connect the accumulator with the secondcylinder through said additional connections, whereby the secondcylinder provides the extra force required to drive the dislodgingmember into the material to be mined for the full stroke of said member.

4. In a mining machine, in combination, a main frame, a carriage mountedby the frame for reciprocating movement, said carriage providing a wedgeplate at its forward end for breaking down the material to be mined,hydraulic motor means for reciprocating the carriage including a maincylinder having a piston operatively connected to the carriage, a fluidpump providing a source of fluid under pressure, a selector valve forselectively directing the pressure fluid to respective ends of the maincylinder whereby to reciprocate its piston and thus the carriage,booster means for the carriage including a booster cylinder having apiston operatively connected to the carriage, an accumulator, meansoperative to charge the accumulator with pressure fluid from the boostercylinder on each return stroke of the piston of said booster cylinder, arelease valve connected to said fluid pump and interconnected with saidaccumulator and said booster cylinder, said release valve being pressureactuated in response to a predetermined maximum pressure developed bysaid pump, whereby the accumulator is released to the booster cylinderduring the forward stroke of the carriage to provide the additionalforce required to drive the dislodging member into the material to bemined for the full stroke of said member.

5. In a mining machine having a main frame, a dislodging member mountedby the frame for reciprocating movement relative thereto, motor meansfor reciprocating said dislodging member to break down the material tobe mined, said motor means including a pair of hydraulic power cylinderssupported by the frame and each having a reciprocating piston connectedto the dislodging member, a source of fluid under pressure, a reservoirfor said fluid, means for selectively supplying said pressure fluid torespective ends of one power cylinder for reciprocating the pistonthereof and thus the dislodging member, an accumulator, a connectionfrom the accumulator to the other power cylinder for supplying fluidfrom the other power cylinder to the accumulator on each return strokeof the piston thereof, whereby the accumulator is charged with pressurefluid when the dislodging member starts its forward stroke, a connectionfrom the reservoir to said other power cylinder for supplying fluidthereto during the forward stroke of the piston thereof,.

a second connection between the accumulator and the other power cylinderfor supplying pressure fluid from the accumulator to said other powercylinder, and valve means in the second connection for controlling therelease of the pressure fluid from the accumulator.

6. In a mining machine, in combination, a main frame, a carriage mountedby the frame for reciprocating movement, said carriage providing a wedgeplate at its forward end for breaking down the material to be mined,hydraulic motor means for reciprocating the carriage including a maincylinder having a piston operatively connected to the carriage, a sourceof fluid under pressure, a selector valvefor selectively directing thepressure fluid to respective ends of the main cylinder, whereby toreciprocate its piston and thus the carriage, booster means for thecarriage including a booster cylinder having a piston operativelyconnected to the carriage, an accumulator, means operative to charge theaccumulator with pressure fluid from the booster cylinder on each returnstroke of the piston of said booster cylinder, a release valve having aconduit connecting said valve with the source of fluid under pressure,said valve being effective when actuated to release the accumulator tosaid booster cylinder, and said release valve being pressure actuated inresponse to a predetermined pressure developed in said connectingconduit, whereby the accumulator is released to the booster cylinderduring the forward stroke of the carriage to provide the additionalforce required to drive the dislodging member into the material to bemined for the full stroke of said member.

7. In a mining machine, in combination, a main frame,

{a carriage mounted by the frame for reciprocating movement, saidcarriage providing a wedge plate at its forward end for breaking downthe material to be mined, hydraulic "motor means for reciprocating thecarriage including a -'main cylinder having a piston operativelyconnected to the carriage, a source of pressure fluid comprising a fluidpump connected to said main cylinder, a selector valve in saidconnection for controlling flow of said pressure fluid, booster meansfor the carriage including a booster cylinder having a pistonoperatively connected to the carriage, an accumulator, a firstconnection between the booster cylinder and the accumulator, a controlvalve in said first connection for trapping fluid in the accumulat'orand which is delivered thereto from the booster cylinder on each returnstroke of the carriage whereby the accumulator is charged with pressurefluid, a reservoir also having a connection to said booster cylinder forsupplying fluid thereto during the forward stroke of said carriage, asecond connection between the accumu- References Cited in the file ofthis patent UNITED STATES PATENTS Number Name Date 2,281,503 Levin Apr.28, 1942 2,330,437 Lively Sept. 28, 1943

